Footwear generally comprises a sole and an upper attached to the sole which surrounds the foot. The upper is removably and adjustably secured to the foot with lacing, which generally crosses back and forth in a crisscross manner over the instep between eyelets in the lateral and medial sides of the upper. As the lace is tightened, the eyelets and hence the medial and lateral sides of the upper are pulled together and tightened.
The upper body of such prior art footwear is often not adjustable except for the laces across the front of the foot. These laces offer only limited adjustment, particularly for regions of the upper that are relatively remote from the laced area, such as the heel, ankle, and forefoot. Such limited adjustment is disadvantageous.
Footwear adjustability is further limited by the fixed location of the eyelets. The location of the lacing determines the location and direction of force vectors developed to secure the foot. While the location of the eyelets may be appropriate for a particular foot, they may not be for a different foot. As there are an infinite variety of foot shapes, fixed location lacing eyelets is hence undesirable. Eyelets are typically rings made of metal or plastic that are affixed to the footwear upper. Such metal or plastic construction is susceptible to breakage, and is known to occasionally separate from the upper under strain of the lacing.
The location of the lacing may also result in user discomfort. As the lacing typically is the only means for adjusting and securing the shoe to the foot, excess tension may be imparted in the laces, and in the upper closely adjacent to the laces. This can result in a disadvantageous compression of the upper on the wearer's instep where the main foot circulatory channels are located, leading to poor circulation through the foot and resultant discomfort.
Also, conventional instep lacing location does not address common problems in retaining a wearer's heel in the footwear. The heel tends to lift and disengage from a sole and from the footwear as the heel is lifted during a wearer's forward movement. This may be particularly true during activities such as sports where very rapid forward movements occur, or when hiking up a steep incline. Traditional instep lacing offers limited means to provide heel retaining support.
Conventional lacing is connected to the sole of the footwear through the medial and lateral quarters of the upper. To offer maximum structural support, these portions of the upper, and in many cases the entire upper, are constructed of heavy weight, high strength materials such as leather, thick canvasses, or heavy synthetic materials. In addition to increasing the weight of the footwear, these materials disadvantageously prevent air circulation. This causes the footwear interior to be uncomfortably hot and humid. For footwear that may be used in a wet environment, such as use during water sports, such heavy uppers disadvantageously do not allow for drainage. Further, heavy materials disadvantageously increase the weight of the footwear.
Also, the upper often loosens over time and with use. As the foot is inserted and removed from the upper, the upper materials may be stretched. After repeated stretchings, the upper will loosen and over time the fit will degrade.
There is therefor an unresolved need for improved footwear having a lacing system for secure attachment of a user's foot to the footwear.